Cathy attended a birthday party where the guests took their shoes off to jump in a bouncy castle. She made this graph to compare the number of people at the party to the shoes on the rack.

What statement best describes the relationship?
A. The relationship is not proportional because the graph does not continue forever.
B. The relationship is not proportional because it does not include negative values.
C. The relationship is proportional because its graph is a straight line through the origin.
D. The relationship is proportional because the number of shoes is always greater than the number of people.